**4. Conclusions**

*Research Trends and Challenges in Smart Grids*

**154**

**Figure 18.**

**Figure 16.**

**Figure 17.**

*Simulation results at DVS (73% SOC).*

*Simulation results at UPS (53% SOC).*

*Simulation results at UPS (78% SOC).*

This chapter presents a hybrid modeling procedure of Li-ion battery-packs which is able to simulate the dynamic behavior associated with electric grid applications. The parameters of an electrical circuit have been calculated from experimental results of current interruption and EIS tests. The active behavior of the battery-pack has been simulated by a voltage source, and the impedance reflects the electrochemical processes by means of three *RC* networks (which correspond to three different time constants) and an ohmic resistance. The experimental procedure has been performed at the whole battery-pack in order to include the interactions of battery cells and BMS components.

To reproduce the battery-pack behavior under high dynamic applications of distribution grids, a hardware-in-the-loop platform has been used. Three different cases (load frequency control, dynamic voltage support, and uninterruptible power supply) at different SOC conditions have been simulated. The validation results show that the hybrid model reproduces the dynamic behavior of the battery-pack with high accuracy in all cases analyzed.
